Ultraviolet leak detection provides an ideal means of determining the exact source of the leakage of a working fluid within an operating system. The operating fluid (e.g., lubricants, hydraulic fluids, heat transfer fluids, refrigerants, etc.) is treated with a small proportion of a fluorescent dye which will enable the operating fluid to fluoresce, even under operating conditions. Any leakage of this treated fluid from the system within which it is operating can be pin-pointed by illuminating the exterior of the fluid-containing components with ultraviolet light. These leak sites will then fluoresce brilliantly, facilitating leak detection.
This technology is especially suited to applications within fields which require the use of pressurized working fluids, such as air conditioning and refrigeration, hydraulics, and compressed gaseous fuels. Any system within which a pressurized fluid flows, and in which the fluid may carry a fluorescent dye, is a candidate for this leak detection technology. Leakage in lines and circuits carrying these types of fluids has been notoriously difficult to reliably detect. However, the superior effectiveness of ultraviolet leak detection allows for pressurized fluid leaks to be located quickly and easily. Accurate ultraviolet leak detection enables operators to keep equipment in an efficient operating condition, conserving power and fluids while providing the maximum effects required for the equipments' application.
A variety of equipment designed to introduce a fluorescent leak detection dye into an operating system is currently available. The equipment can be broadly described as being of either the pre-filled disposable infuser capsule, refillable injector, or refillable displacement type injector varieties.
Both the refillable and pre-filled dye injection equipment operate similarly. Using a refrigeration system as an example, hollow chambers containing dye are connected to a service port on a system and then charged into the system using liquid refrigerant as a propellant. The injectors are basically self-cleaning since liquid refrigerant is flushed through the injector and into the system.
When using the refillable and the pre-filled dye injection equipment described above, care must be taken to avoid allowing the system to become overcharged with the delivered refrigerant. An overcharging of refrigerant can cause system damage from excess pressure or from flooding of the compressor. Decreased system efficiency, due to flooding of the evaporator, is also possible. Further, the use of the refrigerant to introduce the dye also necessitates a connection to heavy refrigerant cylinders or large, cumbersome refrigerant recovery devices.
Prior art refillable displacement-type dye injectors have addressed some of these problems. Such dye injectors allow for the fluorescent dye to be added into a refrigeration or air conditioning system without the need of connecting to any auxiliary source of refrigerant. This permits the user to add dye fluid without adding refrigerant and without the need of connecting to bulky service equipment. Such tools consist of a hollow chamber which is filled with a quantity of liquid dye. The dye is injected into a service fitting by the action of a plunger displacing the dye. This tool basically acts as a syringe, injecting dye into the refrigeration line. Though these devices are convenient because there is no need for refrigerant to act as a propellant, these devices do have a disadvantage in that they must be opened to be refilled.
Any device which incorporates a hollow chamber which must be accessed by a user presents difficulties. The chamber must be filled completely to avoid the possibility of injecting air into a system. The presence of air in a closed liquid system can negatively effect the system's mechanical components and operational performance. Opening the dye reservoir can expose it to contaminants, such as moisture, dust, dirt and particulate matter. Indeed, many of the dyes used for ultraviolet leak detection are very hydrophilic, readily absorbing moisture from the atmosphere. As a result, the purity of the dye used to fill the reservoir may be compromised by the dye having been stored improperly sealed.
Manually filling the tool can also be very messy, as dye material can be spilled or lost to overfilling. Any dye that drips on equipment or is transferred from a mechanic's hands to equipment could result in false leak indications. Any fluorescent traces on a system resulting from dye having dripped from service equipment or elsewhere could be interpreted as being located on actively leaking components, and result in further investigation or in costly repairs which are not necessary. Finally, the refillable displacement type dye injectors must be carefully purged of air before each application. Since no propellant fluid is used to force the dye into the system to be treated, simple purging of air by allowing a flow of propellant is not possible. Any air must be displaced by the dye material.
A currently available applicator utilizing pre-filled chambers of dye is a "caulking gun" style applicator. There are several disadvantages to employing this type of device. For one, the internal mechanism of such tools depends on friction between the moving parts to either advance or restrain the travel of the plunger assembly. This promotes wear on the parts and the tool becomes less effective over time. Because the tool is designed for use with oil-based dyes, small amounts of lubricant from a dye may contact the tool's moving components, resulting in less effective advancement or restraint of the plunger. Effective advancement and restraint of the plunger is absolutely essential for applications dependent upon carefully metered quantities of dye.
In fact, the "caulking gun" style applicator inherently lacks the ability to control the quantity of dye being charged into the targeted system. The lever of the device can be pulled back to any position, advancing the plunger a proportional distance (assuming no slippage). At the same time, the pivoting handle of these applicators only reaches its regulated limit of travel after it is fully retracted into the user's hand. The resulting hand position is uncomfortable and does not promote the efficient application of the necessary significant force to the pivoting handle. A different user may squeeze the handle back a different amount, depending on the size of his hand, his own strength, and the speed at which he performs the application.
If the handle is depressed only part of the way, there is no definitive way for a user to be aware of what part of the necessary dye charge entered the system. As such, the user may have to attempt to "top off" the system with additional dye, resulting in an overcharged system--or in an undercharged system if the user was not aware the dye charge was not completely introduced. In an attempt to mitigate these adverse consequences, "caulking gun" style applicators utilize a highly diluted dye. The use of diluted dyes increases the total quantity of material delivered to a system. The use of diluted dyes is not beneficial since operating systems depend heavily on the quality of the operating fluid. Changes in physical properties could result in system failure.
There is a need for a convenient tool which will allow neat and accurate introduction of fluorescent dyes into pressurized systems. Such a tool would overcome the disadvantages of presently available applicator tools detailed above. Such a tool would also provide a great benefit to service personnel who must maintain them and the owners of such equipment who must finance their operations.